It is known that the natural bone structure is affected and can change from wear, bone weakness (such as osteoporosis) or other osseous changes caused by disease such as tumor diseases in the pelvic area so that the bone statics fail, and/or the joint function, especially that of the acetabulum. Corresponding damage and failure at this location can also occur as a result of accidents and complicated fractures.
Frequently, these are instances in which only the pelvic-side part of the hip joint, the acetabulum and its directly adjacent areas, is affected. In these cases, hip endoprostheses are inserted; an artificial socket component is inserted and anchored in the pelvic bone in a patient's existing pelvis which is otherwise intact in regard to its bone structure and load-bearing capacity instead of the defective, natural acetabulum.
In such cases, however, in which large parts of the pelvic bone are defective and affected, more extensive replacements are necessary.
CN 102048598 A discloses a partial pelvic replacement in which the entire os ilium is replaced in addition to the acetabulum formed thereupon as well as at least part of the os ischium, or the entire os ischium in one version of the embodiment, when there is particularly massive damage to the natural pelvic bone.
The endoprosthesis of the invention is for less extensive and serious replacements, however, and relates to endoprostheses for the partial replacement of the human pelvic bone which cover the region of the acetabulum as well as part of the os ilium.
Comparable endoprostheses which, in addition to replacing the acetabulum, also extend at least to the region of the os iliumare are known from the prior art. For example, a modular reinforcement system for the articular cavity of the hip joint is known from DE 697 29 265 T2. Individual planar add-on modules are provided which can be connected to an acetabulum replacement, and from which selected modules can also extend at least over the os illium. The add-on elements disclosed therein are releasably attached to the acetabulum where they do not serve to replace bone defects in the os illium, for example, but rather enhance the anchoring strength of the acetabulum replacement.
DE 197 47 357 C1, which describes a development of the pelvic partial endoprosthesis disclosed in DE 197 00 160 C1, also discloses a pelvic partial endoprosthesis, wherein a bridge guided over the os ilium and releasably attached to the acetabulum replacement—designated as a bridging piece therein—can be attached to also affix the overall prosthesis created in this manner to this pelvic part. This additional element serves to stabilize the partial endoprosthesis even when the pubic bone is severed, supports the clamping of the fracture by means of claws inserted into the opening between the os ilium, os ischium and os pubis, and exerts tension there, drawing the fracture together.
The latter two known solutions from the prior art especially do not serve to bridge or repair a more extensive bone defect, which also extends into the os ilium, resulting for example from serious injury, that can, however, arise in particular from pelvic bone tumors.